Heightening environmentalists’ fears about the dangers of genetic engineering, a
weed that was altered by scientists to resist an herbicide also developed far greater
ability to pollinate other plants and pass its traits on.

The findings raise the possibility of the emergence of “superweeds” impervious to
weedkillers.

Joy Bergelson, a professor of ecology and evolution at the University of Chicago,
said the findings show that genetic engineering can substantially increase the chances
of “transgene escape,” or the spread of certain traits from one plant to another.

Her study was published in today’s issue of the journal Nature.

Charles Margulis of Greenpeace said the results confirm fears that genetically engineering
cotton and soybeans to survive spraying with herbicides to make weed control easier
will force farmers to spray heavier doses of herbicides or use types that are less
environmentally safe.

“It’s just another chink in the armor of the industry, which keeps saying environmentalists’
claims of health concerns just aren’t justified,” Margulis said.

Scientists have already recognized that when a genetically engineered crop grows
near a weed relative, the gene-engineered trait will eventually transfer to the weed.

In a separate study, Ohio State University scientist Allison Snow found that when
weeds acquire herbicide resistance from genetically engineered crops, they maintain
their ability to pass these traits on, rather than becoming less fertile, as some
had believed.

Bergelson experimented with a weed called Arabidopsis thaliana, a species commonly
used in genetic research.

She compared the fertilization rate of plants that were mutated to make them resistant
to the herbicide chlorsulphuron and plants that were genetically altered for the
same trait.

The genetically altered plants were able to fertilize other plants at a rate 20 times
greater than that of the mutants.

Why this was so is not clear. Bergelson speculated that the pollen from the genetically
altered plants might have a longer life span than normal pollen or have some other
competitive advantage.